Field of the Invention
The present invention generally relates to prosthetic devices and, more particularly, to an olfactory implant system for individuals who have an impaired or lost sense of smell.
Background Description
Information is transmitted in the human body by the nervous system. Electrical pulses, or propagating action potentials, travel along the extensions (axons) of a nerve cell, from one nerve to another (or between many nerves) to create a functional network of communication. Electric pulses begin when the organs of sensation are stimulated. Olfaction, or the sense of smell, is controlled by the olfactory system comprising olfactory nerves. In humans, the odorant-detecting portions of the olfactory nerves are within the nasal cavity where they have exposure and therefore access to odor molecules which are inhaled by the subject. The nerves pass from the nasal cavity through the cribiform plate of the anterior skull base and synapse with 2nd order neurons in the olfactory bulb. In cases where a subject has a damaged or lost sense of smell, it is most commonly due to destruction or interruption of the olfactory nerves. The olfactory bulb in these circumstances usually remains intact and healthy.
Sensors and sensor arrays for the detection and identification of some airborne molecules are known and used to detect odor molecules which stimulate the human olfaction system as well as vapor molecules which humans may not have the ability to smell. Sensors of this kind, which are sometimes referred to as “electronic noses”, are found in food, industrial, and environmental applications, for example. US Patent Publication No. 2006/0191319 to Kurup describes detecting soil born contaminants or volatile organic compounds in soil. This may be useful in areas where industry operations such as hydrocarbon extraction (e.g. hydraulic fracturing, or “fracking”) are performed. Odor detection may be used by a food processing plant to help detect spoiled goods. Carbon monoxide detectors are commonly found in both commercial and residential environments as a safety precaution since humans cannot sense carbon monoxide, which can be lethal if large amounts are inhaled.
Stimulating devices and techniques for electrical stimulation of particular tissues of the human body are also known. U.S. Pat. No. 3,236,240 to Bradley is a very early US patent pointing to stimulation of muscle tissue, in this case the muscles controlling the bladder. Many modern stimulatory applications have been directed to interacting more closely with the central nervous system. Deep brain stimulation, for example, may involve a small linear array of stimulating electrodes which are implanted to provide small low power electrical fields in selected regions of the brain. This has been successfully used for maladies from Parkinson's Disease to depression.
Cochlear implants are another well-known biostimulatory application. A stimulating electrode array is implanted into the human cochlea to artificially trigger action potentials in the human auditory nerves for persons who have impaired or lost capacity for hearing. Electrode arrays have been used with the central nervous system; at the end organs (cochlea, eye, brain, kidney, liver, stomach, muscle or other tissue, for example); and along the nerve pathways, both afferent and efferent, of the peripheral nervous system which bridge the central nervous system with the end organs. Unfortunately not all five human senses are treatable by bioelectrical stimulation means or otherwise in the case of lost or impaired function. For anosmics, or persons who have lost their sense of smell due to injury or disease, there is currently no known means for recreating this important sense.